SOLVENT-RESISTANT HEAT EXPANSIVE MICROCAPSULE

摘要

PURPOSE:To give sufficient solvent resistance and heat expansive property to microcapsule by providing a layer of a thermoplastic polymer softened at higher temp. than the vaporization temp. of a volatile liquid contained in the central part of the microcapsule surrounded by said thermoplastic polymer layer, and a covering layer consisting essentially of gelatin to the outermost surface of the capsule. CONSTITUTION:Volatile liquid 1 (e.g. hexane) is contained in the central part of a capsule; a layer 2 of thermoplastic polymer (e.g. copolymer of vinylidene chloride and acrylonitrile) softened at higher temp. than the vaporizing temp. of the liquid 1 is provided to the outside of said liquid 1; and a covering layer 3 consisting essentially of gelatin is provided to the outermost surface of the microcapsule. Preferred amt. of gelatin for coating the surface of the core capsule is 1-30wt% based on the total dry weight of the double coated microcapsule to be obtd. Further, preferred amt. of the volatile liquid to be contained in the capsule is 3-50wt% based on the weight of the core capsule, more pref. 5- 30wt% for obtg. higher coefft. of thermal expansion. Preferred size of the core capsule is 1-50mu if high coefft. of thermal expansion is desired.